A dishwasher having a condensation drying system is described in DE 198 18 812 A1 or EP 0 755 652 A2. In this appliance, after completion of the water-using cycle steps, cooling air is drawn in by a fan in the lower region of the dishwasher and passed along the side surfaces of the washing tub for the purpose of drying the dishes. As a result, the moisture condenses from the warm moist process air within the washing tub, and collects as condensate in the lower region of the tub.
Other dishwashers (e.g., as described in DE 44 04 113 C2), mix the moist process air inside the washing tub with cold air from outside, and then discharge the air through an opening in the door.
In spite of the aforementioned drying systems, some users open the door after the water-using cycle steps end (generally after the rinse step), so as to achieve drying by convection. In the system described in DE 44 43 849 A1 the latch keeper of a dishwasher with a closing plate which is eccentrically mounted to a motor and thereby can automatically open the washing tub door to an ajar position after the wash cycle is complete. Although the mechanical or automatic opening of the door improves the drying process, problems still arise if the dishwasher is integrated into a row of kitchen units and covered by a countertop. In such conditions, the warm, moisture-laden air condenses on the underside of the cold countertop, which may result in its destruction.
Document JP 08 052 103 A describes a dishwasher in which the moist air from the washing tub is mixed with dry fresh air and discharged from the washing tub above the appliance door. An air duct branching off from the fresh-air intake fan leads into a second opening above the exhaust port. The aim of this is to prevent moisture from the washing tub from condensing on the edge of a countertop above the dishwasher housing. Since the fresh air being drawn in is cool, the dew point at the edge of the countertop is low. Therefore, a very large amount of fresh air must be discharged from the second opening, which impairs the drying performance inside the washing tub.
A domestic dishwasher 1 may include a washing tub 2 which can be closed at is front by a door 3, as is illustrated in FIG. 3. Door 3 is hinged in the lower region such that can pivot about a pivot axis 4. For purposes of stability, washing tub 2 is provided with a U-section metal cross-member 5 (see also FIG. 2). The outer leg 6 of cross-member 5, which is shown on the left in FIGS. 2 and 3, forms the front boundary line of appliance housing 8. The outer leg is provided with a seal 9 which engages the upper edge of door 3. For purposes of noise and thermal insulation, an insulating mat 10 is placed on the washing tub. Generally, a countertop 11 is located above dishwasher 1. The countertop is not part of the appliance, but of the row of kitchen cabinetry into which dishwasher 1 is integrated as a built-in or undercounter appliance. The front edge of countertop 11 projects over door 3 and will hereinafter be referred to as “overhang 12”. The overhang may lie in the plane defined by the door front, or may project even further.
Dishwasher 1 further includes a condensation drying system for removing moisture from the warm, moist air that is present within the washing tub after the last water-using cycle step is completed. To this end, a fan 13 is provided in the lower side portion of dishwasher housing 8. The fan draws in cooling air (symbolized by arrows 15) through an opening 14 in appliance housing 8 below door 3 and passes it along a side wall of the washing tub. The cooling-air flow 15 is completely discharged at the rear, as shown in FIG. 3.
In order to improve the drying performance, dishwasher 1 is also equipped with a device for automatically opening the door to an ajar position at the end of the drying step, similar to that described DE 10 2005 028 448 A1. FIG. 4 shows the upper portion of dishwasher 1 in a slightly open condition. To allow the closing of washing tub 2, a forked latch member 16 is rotatably mounted on door 3. When in the latching position, the latch member is in engagement with a latch keeper 17 mounted on the washing tub. To open the door, a handle 18 is pushed upward, causing latch member 16 to be rotated (via a mechanism not shown) to a position in which it is no longer held by latch keeper 17. To enable door 3 to be opened in a program-controlled manner without actuation of handle 18, latch keeper 17 is attached to a closing plate 19 which can be linearly displaced by motor means over a distance of about ten centimeters in the opening direction of door 3. Motor 20 is energized by controller 30 of dishwasher 1 according to the programmed cycle.